Over the past decade, there has been a huge shift in dentistry going from using amalgam or "mercury" fillings in posterior teeth to being "metal free," via direct resin restorations.

Every day in dental practices all over the world, dental professionals complete one of the most common dental restorations; yet it can be one of the most challenging and under-paid procedures: the Class II direct resin restoration  

When I graduated in 2000 from dental school, we were one of the first classes that had direct posterior resin restorations as part of our dental school curriculum, and we were assured that in the future we would all be “bondodontists” meaning that we were going to be bonding everything.  At that time, posterior resin restorations or “white fillings,” were thought of being “pretty,” but not long lasting, and on top of that, they were even more technically challenging and time consuming to place than a regular amalgam or “silver” filling.  So, it raised the question: “Why would you put a tooth-colored filling in a back tooth? ”   Well, here we are 15 years later: bonding and posterior resin restorations are very much mainstream dentistry as patient demand along with material advances,  have made them predictable and long lasting. 

resin restorations
Wooden and plastic wedges

Over the years, I have found that one of most challenging restorations and one that can be time consuming is the class II posterior resin restoration.  On top of that, if you compare the time you spend placing a very nice class II resin restorations from start to finish to other restorations we complete, especially ones that incorporate more than a few surfaces, it can be difficult to get paid on the same order as we do for many other procedures. 

So, what have I learned after placing direct resin posterior restorations for 15+ years and why are they more challenging than other direct dental restorations, especially the class II ones? First off, like all restorative procedures, especially the ones that require bonding, you have to keep it isolated from saliva, blood and other contaminants. 

Another big challenge, if not one of the biggest ones, in placing and doing a great class II resin restoration, is to get ideal contours and ideal interproximal contacts.  If you are like me, I learned using the good old tofflemire matrix, which had been used forever doing class II amalgams, and it worked great…..for amalgams!  I found even when I burnished, wedged and pre-wedged these older type matrix bands, I would be praying that I got a good proximal contact, even if it didn’t have the greatest contours.  Sound familiar?  Once I got out of dental school, it didn’t take me long to decide that there had to be a better way: the sectional, pre-contoured matrix band and retaining rings was the magic I needed to make class II resins predictable and straightforward.  I have used a variety of these systems over the years, and they work (some better than others) well for a typical class II restoration and you get tight proximal contacts and nice contours.  Unfortunately, they do have their drawbacks too: if you are missing too much tooth structure or the proximal boxes extend too far onto the facial or

restorations
Halogen light vs. LED

lingual, then it can be a difficult to keep them in place. 

It’s critical to make sure you have the gingival margin area dry and not seeping between the tooth and your matrix band, which can be managed well with a wedge.  Even wedges have changed: we used to have only wooden ones but now we have plastic ones that are pre-shaped, flexible, etc. 

Now, you have your tooth isolated, matrix band in place and now you have to do a great job placing your bonding agent of choice: that means following manufacture’s recommendations to a “T,” placing an adequate amount onto the properly prepared dentin surface and curing it adequately.  In class II restorations, this can be challenging since the proximal box can difficult to access adequately and to evenly distribute the bonding agent and avoid “pooling” of the bonding agent.  These things alone will help you tremendously with another common issue and often frustrating issue with posterior resin restorations: sensitivity.  I’m sure if you have done enough of them, you have had at least one that is sensitive:  Some a little, some a lot.  Either way, you and your patients won’t be real happy if you get a lot of phone calls and post-op appointments trying to sort out why their tooth is sensitive now versus no problems before.    

Finally, you are ready to place the resin, but wait, do you bulk fill, incrementally fill, use a flowable liner, etc.?  The list goes on and on, but personally, I have found that using a little flowable resin that is radiopaque is helpful managing the adaptation of the resin in the proximal box and how I place the resin depends on the depth and size of the proximal box.  And a quick curing, high-intensity curing light will save you a lot of time over the course of a year, so it’s worth every penny you spend on it. 

Class II Resin Restorations
Evolution of Matrix Bands

Once you get your matrix band out of the way, you have to make sure there is no flash or overhangs present, and if you did a great job placing your wedge and matrix band, then this will be minimum at most.  I have found a good Bard Parker handle with a #12 blade or a nice sharp scaler to be really helpful managing these difficult-to -ccess areas.  It is then we are ready to adjust the occlusion, floss (sometimes, it is even hard to get floss through; a good serrated metal finishing strip is great for helping with this along with getting rid of any bonding agent between adjacent teeth) and polish.

I will then often get the patient, unless their tongue is numb, to run it over the restoration.  It’s a great way to find any rough or sharp areas that you may have overlooked.  And if you are wanting a great way to finish it so that it is as smooth as the natural tooth: use a felt polisher and some diamond polishing paste running in a slow speed dry on the tooth and allow it to run until the polishing paste disappears. 

Now, you are done!  So, as you can see,  posterior resin restorations, especially class II ones, can be challenging and time consuming, yet can be a great service to your patients. 

Jeff Lineberry, DDS, FAGD, FICOI  Visiting Faculty and Contributing Author, Spear Education


Comments

Commenter's Profile Image Parisa S.
July 27th, 2015
Hi Jeff, Thanks for the article. I used to place flowable composite at the inter proximal gingival floor, but stopped doing it due to the shrinkage factor. Is there a brand of flowable composite that shrinks less? Thank you!
Commenter's Profile Image Jeff L.
July 27th, 2015
Parisa Thanks for the question. Personally, I like Clearfil Majesty Flowable. The reason I like it is that it has a high filler volume (81% wt), low shrinkage ratings, and is highly radiopaque (which is important for future evaluation of the restoration radiographically). Depending on the restoration, I will either use this to start alone and place a thin layer, or sometimes I will place a small amount to "wet" the prep and then inject my regular resin into it to begin filling the proximal box, allowing the excess flowable to express out. Hope this helps. (**Disclaimer: I have no financial interest in any company) Thanks again. Jeff
Commenter's Profile Image Amanda A.
July 28th, 2015
Thanks so much for the article. I am a fairly new associate and have been butting heads with my boss regarding this topic since I began. He has told me that any interproximal caries warrants treatment with an indirect restoration, and tells all of our patients that composite will only last 5 years and thus is a short term solution at best. In fact, he actually gets angry with me if I place class II composites because according to him I am providing inferior treatment and throwing away my production. I am torn: is my boss just money-hungry (he charges 6 times the price for a 2 surface inlay vs 2 surface composite), or is he providing me legitimate, good advice to steer my patients to the best treatment possible? Since I have only practiced for 2 years, I do not have the experience to support or reject the durability or Class II posterior composites, but I would love if more seasoned dentists would weigh in on this topic. Thanks again!
Commenter's Profile Image Barry H.
July 28th, 2015
Parisa, your concern is valid in that you do need to be careful if using flowable in your Cl. II box due to the shrinkage factor and even more so in cases where have minimal to no cervical enamel. In these circumstances, you might be best to either consider a flowable that is more heavily filled (such as Kuraray Clearfil Majesty Flow) and use in very thin layers (no more than 1 mm thick), or consider using a sandwich technique where place Glass ionomer or RMGI at the gingival margin and overlay it with composite. Another technique I have found to be very helpful is when placing your composite for the gingival increment and to ensure better adaptation to the box line angles, I will go back with my applicator that I used for placing the adhesive and having it just barely moist (don't want it wet as would dilute the restorative composite) with adhesive (must be a pure adhesive, not one that is combined with primer), use it to "condense" and adapt the composite to the tooth with a gentle tapping motion. If using a very highly viscous restorative composite, this technique may not be as effective however. If that is the case, may wish to use a carpule warmer for better adaptation of the composite to the tooth. Just my thoughts...
Commenter's Profile Image Jerry R.
July 29th, 2015
I don't often place CII composites when the proximal box extends passed the buccal and/or lingual line angles, but sometime you must. I highly recommend ABC wedges along with the sectional matrix for such circumstances - the wedge has a plastic form which contours and supports the matrix and prevents the clamp from compressing in the line angle you are trying to create. There are three sizes and "right" and "left" to accommodate all the posterior teeth. Takes a little time to figure them out, but they are an Ace in your back pocket when you need one. NO financial interest in ABC's.
Commenter's Profile Image Huixin W.
October 24th, 2018
Jeff, thank you for sharing, may I ask what system you use for class II matrix?